Modern integrated circuit fabrication techniques enable new ways of interconnecting integrated circuit die to achieve a small size. The small size integrated circuit dies are especially useful in small portable electronic devices such as mobile phones, personal digital assistants, and the like. One such technique is through-silicon via (TSV) technology. TSV technology is a three-dimensional packaging technology that enables vertical die stacking by utilizing metal-filled via holes. TSV stacked die reduce interconnect distances in comparison to conventional multi-stacked wire bond silicon chips, thereby enabling faster speeds and lower power consumption for a data processing system.
TSVs may be used to conduct signals from one surface of the die to the other, and enable the construction of vertical stacks of die. For example, memory dies may be vertically stacked to form a three-dimensional (3D) memory “cube” which occupies a very small volume. However, known vertically stacked die are electrically connected using micro-bumps that have a relatively large surface area on the die and add a large capacitance that limits the interconnect speed.
In the following description, the use of the same reference numerals in different drawings indicates similar or identical items. Unless otherwise noted, the word “coupled” and its associated verb forms include both direct connection and indirect electrical connection by means known in the art, and unless otherwise noted any description of direct connection implies alternate embodiments using suitable forms of indirect electrical connection as well.